Christmas from the Heart, which opens the Circa '21 Dinner Playhouse's 29th season, is a holiday-themed musical revue, and as such, it has a built-in advantage that many stage works don't: Audiences don't make many demands of it. When presented with a piece of this sort - in which the production is essentially an excuse for linking together a diverse group of carols and holiday hits - no one really cares what the story is about or whether the characters have any depth; all we ask is that the numbers are well-sung and that the show maintains a lively pace, and if it's funny or touching or particularly well-designed, those are just added bonuses.